Cochlear Implant

Cochlear Implants

What is a cochlear implant ?

A cochlear implant is a small, complex electronic device that can help to provide a sense of sound to a person who is profoundly deaf or severely hard-of-hearing. The implant consists of an external portion that sits behind the ear and a second portion that is surgically placed under the skin (see figure).

A microphone, which picks up sound from the environment.

A speech processor, which selects and arranges sounds picked up by the microphone.

A transmitter and receiver/stimulator, which receive signals from the speech processor and convert them into electric impulse.

An electrode array, which is a group of electrodes that collects the impulses from the stimulator and sends them to different regions of the auditory nerve.

An implant does not restore normal hearing. Instead, it can give a deaf person a useful representation of sounds in the environment and help him or her to understand speech.

How does a cochlear implant work ?

A cochlear implant is very different from a hearing aid. Hearing aids amplify sounds so they may be detected by damaged ears. Cochlear implants bypass damaged portions of the ear and directly stimulate the auditory nerve. Signals generated by the implant are sent by way of the auditory nerve to the brain, which recognizes the signals as sound. Hearing through a cochlear implant is different from normal hearing and takes time to learn or relearn. However, it allows many people to recognize warning signals, understand other sounds in the environment, and enjoy a conversation in person or by telephone.

The ear is comprised of three parts : -

The outer ear
Consists of the pinna (visible outer portion) and ear canal

The middle ear
Consists of the eardrum, ossicles (three small bones) and middle ear space

The inner ear
Consists of the snail-shaped cochlea and organs of balance

Who gets cochlear implants ?

Children and adults who are deaf or severely hard-of-hearing can be fitted for cochlear implants. According to the Food and Drug Administration (FDA), at the end of 2006, more than 112,000 people worldwide had received implants. In the United States, roughly 23,000 adults and 15,500 children have received them.

Adults who have lost all or most of their hearing later in life often can benefit from cochlear implants. They learn to associate the signal provided by an implant with sounds they remember. This often provides recipients with the ability to understand speech solely by listening through the implant, without requiring any visual cues such as those provided by lipreading or sign language.

Cochlear implants, coupled with intensive postimplantation therapy, can help young children to acquire speech, language, and social skills. Most children who receive implants are between two and six years old. Early implantation provides exposure to sounds that can be helpful during the critical period when children learn speech and language skills. In 2000, the FDA lowered the age of eligibility to 12 months for one type of cochlear implant.

How does someone receive a cochlear implant ?

Use of a cochlear implant requires both a surgical procedure and significant therapy to learn or relearn the sense of hearing. Not everyone performs at the same level with this device. The decision to receive an implant should involve discussions with medical specialists, including an experienced cochlear-implant surgeon. The process can be expensive.

For example, a person's health insurance may cover the expense, but not always. Some individuals may choose not to have a cochlear implant for a variety of personal reasons. Surgical implantations are almost always safe, although complications are a risk factor, just as with any kind of surgery. An additional consideration is learning to interpret the sounds created by an implant. This process takes time and practice. Speech-language pathologists and audiologists are frequently involved in this learning process. Prior to implantation, all of these factors need to be considered.

What is the process ?

Once a person is referred to the cochlear implant center extensive testing is done to determine whether the person is a suitable candidate. This evaluation usually includes extensive audiologic testing, psychological testing, examination and tests performed by the surgeon, X-rays, MRIs, physical examination, and counseling to ensure suitability and motivation to participate in the process. It is important that the candidate understands what the implant will and will not do and also understands the commitment required for care and follow-up services.

Once the decision is made to go ahead, the surgery is done. Sometimes it involves an overnight stay in the hospital, and sometimes it is done on an out-patient basis.

About 4-6 weeks after surgery, the person returns to the center to be fit with the microphone and speech processor and to activate and program (called mapping) the implant. The initial fitting process is done over several days and may include additional visits over several months. The reason is that, as each electrode in the cochlea is activated, it must be adjusted and programmed into the speech processor. As the person develops skill in using the implant, further adjustments and reprogramming is required. Once the optimum program is obtained, fewer visits are required. Usually there are annual visits to the center for checkups.

Both children and adults receive extensive rehabilitation services from audiologists, speech-language pathologists, teachers, and counselors as they learn to listen, improve speech, use speech-reading, and handle communication. They are taught how to use the implant and how to respond to the sounds they are receiving. For those who have heard before, sounds through the cochlear implant may seem unnatural at first. Those who have never heard must be taught what the sounds are.

Who is best suited for a cochlear implant ?

Research is constantly providing new information and technology resulting in changes in cochlear implant procedures and instrumentation.

It is generally agreed that the best adult candidates are those who : -

Have severe to profound hearing loss in both ears

Have had limited benefit from hearing aids

Have no other medical problems that would make the surgery risky

Have a strong desire to be part of the hearing world and communicate through listening, speaking, and speechreading.

Children can also be candidates for cochlear implants. Children as young as 14 months of age have received cochlear implants, and the potential exists for successful implantation at younger ages.

It is generally agreed that the best child candidates are those who : -

Have profound hearing loss in both ears

Can receive little or no useful benefit from hearing aids

Have no other medical conditions that would make the surgery risky

Are involved (when able), along with their parents, in all aspects of the informed consent process

Understand (when able), along with their parents, their individual roles in successful use of cochlear implants

Have (when able), along with their parents, realistic expectations for cochlear implant use

Are willing to be involved in intensive rehabilitation services

Have support from their educational program to emphasize the development of auditory skills.

Patient Storys

Successful heart surgery at We Care India partner hospital allows Robert Clarke to live a normal life despite a rare genetic disorder We Care india helped Robert find best super specialised surgeon for his rare conditions.